Question: is {cast member} of {Buffy the Vampire Slayer} that is {character role} is {Buffy Summers} ?
Paraphrase: is {cast part} of {Buffy the Vampire Slayer} that's {character part} is {Buffy Summers} ?
SPARQL (Wikidata): SELECT ?obj WHERE { wd:Q183513 p:P161 ?s . ?s ps:P161 ?obj . ?s pq:P453 wd:Q1799459 }